labthings_fastapi.dependencies.raw_thing
========================================

.. py:module:: labthings_fastapi.dependencies.raw_thing

.. autoapi-nested-parse::

   FastAPI dependency to obtain a `.Thing` directly.

   This module allows actions to obtain a `.Thing` instance without the
   `.DirectThingClient` wrapper. As a rule, it is best to use `.DirectThingClient`
   where possible.



Attributes
----------

.. autoapisummary::

   labthings_fastapi.dependencies.raw_thing.ThingInstance


Functions
---------

.. autoapisummary::

   labthings_fastapi.dependencies.raw_thing.find_raw_thing_by_class


Module Contents
---------------

.. py:data:: ThingInstance

.. py:function:: find_raw_thing_by_class(cls: type[ThingInstance]) -> Callable[[fastapi.Request], ThingInstance]

   Generate a function that locates the instance of a Thing subclass.

   .. warning::

       Using a `.Thing` directly can be tricky: unless you really need to, it is
       usually better to use a `.DirectThingClient`, which provides an interface
       that should be identical to the HTTP thing client in Python. This is safer,
       and means code should be easier to translate between server and client-side.


   In order to access the instance of ``OtherThing`` attached to your thing server,
   declare your argument type as:

   .. code-block:: python

       OtherThingDep = Annotated[
           OtherThing, Depends(find_raw_thing_by_class(OtherThing))
       ]


       def endpoint(other_thing: OtherThingDep):
           pass

   LabThings will supply this argument automatically through the :ref:`dependencies`
   mechanism.

   Note that this function *returns* a dependency - it should be called with
   arguments inside `fastapi.Depends`.

   :param cls: is the `.Thing` subclass that will be returned by the dependency.

   :return: a dependency suitable for use with `fastapi.Depends` (see example).